Troubleshooting GGG Big Muff Pi

[Maakali]

Working on a GGG Big Muff Pi, Civil war version...

Wiring diagram: http://www.generalguitargadgets.com/pdf/ggg_bmp_wiring.pdf
Schem : http://www.generalguitargadgets.com/pdf/ggg_bmp_rusc_sc.pdf
BOM: http://www.generalguitargadgets.com/pdf/ggg_bmp_rusc_bom.pdf
Layout: http://www.generalguitargadgets.com/pdf/ggg_bmp_rusc_lo.pdf

Passes signal when bypassed, when engaged I get a low volume high pitch whine, and I really have to crank the knobs to hear it.

Getting weird voltages to Qs 1, 2 & 4, though Q3 is in the ballpark.  Input voltage 9.2v
Q1 E 0.267v
     B 0.886v     
     C  0.892v
Q2  E 0.268v
      B 0.889v
      C 0.268v
Q3  E 0.204v
      B  0.812v
      C 3.314v
Q4  E 7.19v
      B 7.92V
      C 7.15v

It's driving me a bit batty and I figure I'm at the point where I'm just not seeing something that should be obvious.  Any suggestions would be greatly appreciated.

[Marcos - Munky]

First thing, welcome!

While Q3 seems to have the most correct voltages, almost all of them seems to be off. To begin, since Q2 and Q3 stages are equal, they should have the same voltages.

Post photos of your board, both sides. My first guess is a wrong value resistor, but we have to check to be sure. Or is could be something else we can find when looking at your board.

Also, do you know how to do an audio probe test?

[antonis]

Hi & Welcome also..

As already Marcos said, it's probably a "silly" wiring issue, mainly located on Positive Collectror connections..

ALL B-E junctions behave well & healthy..!!

[Maakali]

Images

[Govmnt_Lacky]

Check R3, R10, and R22. R22 definitely looks like a 470 ohm resistor. Supposed to be 470K.

Make sure same mistake wasn't made in R3 and R10.

[Marcos - Munky]

Ah crap, I hate those coloured resistors. They're so hard to read.

R2, R10 and R22 looks like 470r to me, when they should be 470K. For the blue ones, I can't say anything. It's usual for some colors end up blending with the blue from the resistor, creating a totally different color, so I can't say they're correct or wrong.

[Phend]

Measure twice, solder once. (DMM)

[antonis]

First of all, verify firm conduct of all transistor legs with respective sockets..

[Maakali]

O man I can tell you right now, without even looking at the pics going to the workbench, that those are definitely 470r.  I remember which bin I got them out of.  I'll get those swapped out today and will post the results.  Many thanks.

[Maakali]

I'd like to thank everyone who participated in this July 4th Weekend edition of "Spot Dave's Dumb Mistake."  You have my eternal gratitude.

Swapped out the 470r for the correct 470k and she works like a dream. 

Honestly, the minute I saw the 470r mentioned I knew I had grabbed parts from the wrong bin.  I just couldn't see that at the time.

Pics of finished product attached.

My thanks again to all.

[Marcos - Munky]

Ah don't worry on that, happens to us more often than you think. And we usually check lots of times and can't see a wrong value part, then somebody finds it by just doing a quick look at a photo.

Glad to hear it's working now!

[Gordo]

Great looking build!

[POTL]

good build, but the inscriptions in Russian is an epic failure.

I remembered an old meme from a series of films about the Bourne.